Fuse



April 12, 1927.

C. W. ENGLEMAN FUSE Filed May 4, 1925 gyn/vento@ Mj/Qa/e/mr/f Patented Apr. 12, 1927.

CHARLES W. ENGLEMAN,\OF ABILENE, KANSAS.

FUSE.

Application led Hay 4,

This invention relates to an improved fuse, of the kind adapted to be .incorporated in an electric circuit, so that when there is an overload ot current passed through the eircuit, such as is the case under abnormal conditions, the fuse will interrupt the passage of the current, until the normal condition is resumed. L

The purpose of the invention is to provide a fusewhich is automatic in'operation, thus obviating the necessity of renewing or refilling, as is essential with the ordinary tube and cap fuse.

More particularly, the invention has reference to a fuse, which embodies a current conductor, preferably mercury, which, under normal conditions vspans the space between the usual terminals and serves to convey current from one tothe other, the mercury being vaporized and otherwise affected, under a predetermined heat to momentarily break the circuit, but resuming its normal shape under normal conditions.

The articular construction employed for accomplishing this result'will become apparent from the following description and drawing.

In the accompanying drawing, forming a part of this application, and in which like numerals are employed to designate like parts throughout the same:

Figure 1 is a central longitudinal section through a fuse constructed in accordance with this invention, showing one embodiment of the same.

Figure 2 is a like view, showing a different embodiment of the invention.

Attention is first directed to Fiure 1, wherein a body of insulation material, preferably glass is shown. In this instance, the body is formulated to provide a central hol- .low ball 1, which is' open at its bottom. Exy A tending from the open bottom, on diametri-l l cally opposite sides are integral branches 2 and 3, which incline slightly downward and outward. It will be noted that these branches are bored to provide main passages 4 and 5 respectively andaux'iliary passages f6 and 7 respectively. The'auxiliary passages communicate at t eir outer ends with the main passages, the main passages being closed at their outer ends. The'inner ends of the main passages open into the central opening 8, at the bottom of the ball 1. yThe current.

1925. sum1 no. 27,969.

auxiliary passages communicate with small ducts 9, which, in turn, communicate with the chamber provided upon the interior of the ball. Fitted upon-the opposite ends of the branches are caps l() and 11 of electricity conducting material, these caps being provided with pins 12, serving as contacts. These contact pins extend into and have portions exposed in the main passages 4 and 5. As before stated, these passages are llled with mercury which serves as a conductor between the caps 10 and l1 through the medium of the vcontact pins 12. The caps, in practice, will be provided with appropriate terminals (not shown), by means of which customary conducting wlres may be connected therewith. l

Observing Figure 2 now, it will be seen that a somewhat larger hollow ball 13 is provided, there being a single stem depending from this ball, and this stem being formed' with main and auxiliary passages 14 and 15 respectively, in which the mercury conductor is confined. The upper end of the stem projects into the interior of the chamber provided in the ball 13 as indicated at 16. 'lhe upper ends of the passages 14: and 15 communicate with the chamber through the extension. Also, a pair of diagonal ducts 17 afford means by which the fluid is returned to its normal position. Furthermore, a cap 18 is tted on the lower end of the stem and provided with a contact pin 19, and a sleeve 20 surrounds the upper portion of the stem, being provided with an appropriate contact 21. As in the rst instance, this sleeve and cap Will be rovided with appropriate terminals or bin ing posts (not shown.)

In operation, it will be found that there is sufiicient mercury contained in the passages to accommodate the normal amount of current. mal, it' will act upon the mercury to heat and vaporiz'e a portion thereof which will collect in the spherical air tight chamber. The subtraction thus made by this 4vaporization will reduce the mercury conductor to a state to render it insufficient to carry the In this way, the circuit wi-llv be temporarily broken. As the heat reduces the vaporized mercury will automaticall return to its original state and flow bac into and fill up the main passage to provide lVhen the current becomes abnoran unbroken fluid conductor. Thus, the operation o the fuse will be automatic according to the condition of the circuit.

The purposes of providing the auxiliary passages and the ducts which lead from these auxiliary passages to the hollow bore will now be discussed. In order to provide a reloading fuse which will operate as quickly as possible, it must have a quick return for the mercury. Fuses of this type have a small carrying capacity in amperes for high voltage must have an auxiliary passage to let the hot gas out or the mercury would get gas or air bound and would not return in the tube or passage provided therefor for some length of time, if at all, therefore, the mercury could not properly function in again closing the circuit without these auxiliary passages.

Furthermore when the arc is started by blowing of the fuse there is a flaming are created in the fuse and the auxiliary passages carry enough vapor gas to hold the naming are as long as the load stays on, and therefore when the load is dropped, the fiaming arc stops and then reloads the fuse at once by leaving the hot gases out through the ducts and auxiliary passages, thus effecting the reloading of the fuse immediately. These auxiliary passages 6 and 7 and the ducts 9 form an air vent, and also a means for letting the hot gases escape to efect a quick reload.

It is believed that persons familiar with circuit makers and breakers and particularly with thermal devices will be able tov obtain a clear understanding of this invention. I

For this reason, a more lengthy description is thought unnecessary.

While the preferred embodiment of the invention has been shown and described, it is to be understood that minor changes coming within the field of invention claimed may be resorted to, if desired.

I claim:

A fuse of the class described con'ip'rising a hollow ball which is open at its bottom, a pair of branch pipes extending laterally from the bottom of the ball in opposittI directions and being inclined slightly downwardly toward their outer ends, the inner opposed ends of the branch pipes communieating with the open portion of the hollow ball, caps fitted over the ends of the pipes,

said pipes being adapted to contain a quantity of mercury, contacts carried by the caps and extending into the respective ends of the pipes, the mercury normally -bridging said contacts, each of said branch pipes being provided with a longitudinally extending air passage which communicates with the outer end of the respective pipe, the hollow 4ball being provided with ducts which afford communicationbetween the inner end of the air passages and the interior of the hollow ball.

In testimony whereof I aiix by signature CHARLES W. ENGLEMAN. 

